Hydraulic actuator mechanism



May 2, 1950 E. J. SVENSON HYDRAULIC ACTUATOR MECHANISM 10 Sheets-Sheet 1 Filed NOV. 7, 1946 INVENTOR. 'ueizaow BY ijrnaii ATTORNEYfi.

May 2, 1950 E. J. SVENSON HYDRAULIC ACTUATOR MECHANISM 10 Sheets-Sheet 2 Filed Nov. 7, 1946 has L. w WV SH TNQ SN y 2, 1950 E. J. SVENSON 2,505,809

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HYDRAULIC ACTUATOR MECHANISM 1O Sheets-Sheet 4 INVENTOR.

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HYDRAULIC ACTUATOR MECHANISM Filed Nov. 7, 1946 10 Sheets-Sheet 5 INVENTOR i l weal J'verzaaw ATTORNEYfi May 2, 1950 E. J. SVENSON HYDRAULIC ACTUATOR MECHANISM 10 Sheets-Sheet 6 Filed Nov. 7, 1946 I N VEN TOR. 7 726.55 (I506 wow B Y. s

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HYDRAULIC ACTUATOR MECHANISM Filed Nov. '7, 1946 10 Sheets-Sheet 8 ATTORNEYJ'.

May 2, 1950 E. J. svENsoN HYDRAULIC ACTUATOR MECHANISM Filed NOV. 7, 1946 10 Sheets-Sheet 9 INVENTOR. firrzai Jjuerzdam Mam QQR

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zi zag HYDRAULIC ACTUATOR MECHANISM Filed Nov. 7, 1946 Jfzi Patented May 2, 1950 UNITED STATES PATENT oi-"Pics Ernest J. Svenson, Rockford, Ill, assignor to Col-position, Chicago, 111., a corporation of Illino Application November 1,1946, Serial No. 108,339

This invention relates'to hydraulic actuator mechanisms, more particularlyoi the type which :1 Claims. (01. ctr-52) may be used for shifting or propelling various Y struction which will accurately, eiiiciently and economically shift or propel various machine parts, and which may be used to supplant more complicated mechanical mechanisms heretofore used for like purposes.

A'further object of the invention is to provide a hydraulic actuator mechanism which may be used to shift machine elements or parts in timed relation to the operation of other parts or elements including other hydraulic actuator mechanisms; but wherein the operations in each instance may be readily and simply controlled by the operator either directly or remotely. as by the manipulation of a push button, control knob or the like. In accordance with the invention simple electrical means may be utilized for correlating and timing the movements of the actuator, thereby dispensing with complicated mechanical interlocking mechanisms.

A further object of the invention is to provide a hydraulic actuator mechanism of the type stated which may be readily adapted for the shifting of 7 machine parts which are subjected to unusual, severe or specialized operating conditions. For

example, and as will hereinafter be set forth, the

invention may be used for the shifting of valves or the like subjected to extreme variations in temperature, and wherein thevalve must be closed with a predetermined accurately controlled pressure, and wherein additional force is required for breaking the valve away from its seat initially upon the valve-opening operation.

A still further object of the invention is to provide for use with hydraulic mechanisms of the type stated, a new and improved pump construction.

The hydraulic actuator mechanism of the in- "of printing press rollers.

. 2 operation of other machine parts or similar bydraulic operating mechanisms.

A still further object of the invention is to provide, in a hydraulic actuator mechanism of the type defined, improved remote control and indicating means for controlling and indicating the shifting of. the actuated machine part.

Various objects, advantage; and features or the invention other than those hereinbefore speclfically referred to; will appear from the following specification when taken in connection with the accompanying drawings wherein certain prcferred embodiments of the invention are illustrated. I

This application is a continuation-in-part of my prior copending-application now abandoned,

Serial No. 271,444,,flled May 3, 1939, and entitled Hydraulic actuator mechanism.

In the drawings, wherein like reference numerals refer to like parts throushoutz.

Fig. 1 is a general assembly view somewhat diagrammatic in form, showing the invention in one of its embodiments as applied to the shifting Fig. 2 is a viewon an enlarged scale of the hydraulic actuator mechanism as embodied in the structure shown in Fig. "1.

Fig. 3 is a detail view of the actuating mechanism for the control or limit switc Fig. 4 is a detail view of the switch taken'on the line 4-4 of Fig. .2.

Fig. 5 is a detailsectional view of the pump structure and associated parts, taken on the line 5-5 of Fig. 2. r

Fig. 6 is a sectional view through the pump gird {actuator cylinder, taken on the line 6-6 of Figs. 7, 8' and 9 are sectional views of a modie iied form of pump structure, Figs. 8 and 9 being gaiker; on the line 8-4 and 9-9 respectively of Fig. 10 shows the wiring diagram for the form of hydraulic mechanism shown in Figs. 1 to 9 inclusive. V

Fig. 11 illustrates a modified form or embodiment of the invention as of valves or the like.

Figs; 12 and 13 are sectional detail views, on an enlarged scale, of the actuator structures shown in Fig. 11, and taken on the lines "-42 and l3-l3 respectively thereof.

Figs. 14, 15 and 16' are detail sectional views of a part of the controlling switch mechanism, as embodied in the form of construction shown in Figs. 11, 12 and 13. Fiss. l5 and 16 being taken applied tothe operation 3 on the lines i8-|8 and I8-I8 respectively of Fig. 14, and Fig. 14 on line l4- Il of Fig. 12.

Fig. 17 is a sectional view of another part of the switch mechanism as employed in this embodiment of the invention, on the line lI-Il of Fig. 12.

Figs. 18 and 19 are partial views showing the switch device of Fig. 17 in two of its operating positions.

Fig. 20 is a detail sectional view of the lower portions of the valve structure.

Figs. 21 and 22 are detail views showing the mechanism of Fig. 20 in two of its operating positions.

Fig. 23 is a view, somewhat diagrammatic in form, showing a modified form of valve operating structure incorporating locking means for holding the valve in closed position.

Fig. 24 is a detail view illustrating a modified form of locking element.

Fig. 25 is a wiring diagram for the structures shown in Figs. 11 to 24 inclusive.

Fig. 26 is a view similar to Fig. 12, but illustrating a modified form of valve shifting structure incorporating remote control and indicating means, and

Fig. 27 is an electrical circuit for the structure of Fig. 26.

In Figs. 1 to 10 of the drawings embodiments of the invention are illustrated wherein the hydraulic actuator mechanism is utilized for shifting printing press rollers, and in Figs. 11 to 27 inclusive embodiments are illustrated for shifting valves or the like, as the invention in certain of its aspects is particularly adapted for uses of this character. However, it is to be understood that other aspects of the invention may be used with various types of structures, including hydraulic actuator mechanisms for shifting other types of machine parts.

Referring to the embodiments of the invention illustrated in Figs. 1 to 10 inclusive, and first to Figs. 1 through 6, the structure shown comprises a. machine diagrammatically indicated at i8, which may be a printing press, paper handling machine or the like having three hydraulic actuator mechanisms indicated at I2, I 4 and I8 for shifting the printing or paper engaging cylinders. As best shown in Fig. 2, each of these hydraulic actuator mechanisms comprises in general a reversible electric motor I8 adapted to drive a gear pump or the like 28 mounted within a liquid reservoir 22. The intake and exhaust passages of the pump are hydraulically connected to a reciprocable hydraulic actuator 24 which. through a suitable mechanical linkage, shifts the roller or blanket cylinder 28 upwardly out of engagement with the pressure cylinder 38 or downwardly into engagement with said pressure cylinder 38 and associated paper supporting web 3| as the ocgiasion may require to effect the printing opera- Referring to each of the hydraulic actuators more specifically, frame brackets 32 at each side of "the machine rotatably support a bushing 88 which eccentrically carries the mounting shaft for the shiftable blanket cylinder 28. The plate cylinder 28 and the pressure cylinder 38 are provided with mounting shafts journaled at each end in the brackets 32. The eccentric bushing 24 Is rotated or shifted angularly through a predetermined arc to move the blanket cylinder 28 toward and from the pressure cylinder 38 and associated web. as previously stated. The hydraulic actuator 24. which causes this movement of the blanket cylinder. comprises specifically a cylinder 88 cast integrally with the outer end wall of the pump 28. a piston 88 carried by a piston rod 88, and end plates or covers 42 with the usual sealing means or gasket 84 and piston rod packing means 48. The piston rod 88 carries at its outer or upper end a yoke member 48 slidably mounted in a guide bracket 88 secured to the main frame bracket 22. A link 82, Figs. 2 and 3, extends between the spaced arms 84 of the yoke 88 and is pivoted to said arms at its lower end as by a pin 88. The link 82 is pivotally connected by a pin 58 to a crank 88 secured to a shaft 82 journaled in the main frame bracket, shaft 82 being in turn secured to a gear segment 88. The segment 84 meshes with a gear 88 mounted on a stud shaft 88 carried by the frame bracket 22, the stud shaft also carrying a disk 18 to the face of which is pivoted a link I2 pivotally connected to a crank I4 secured to or formed integrally with the eccentric bushing 84. It will be evident that upon reciprocation of the piston 38 the segment 84 will be oscillated through a predetermined arc and this segment in turn will cause oscillation of the eccentric bushing 34 through a predeter mined arc and thus move the blanket cylinder 28 toward and from the pressure cylinder 88. It should also be noted that the parts of the mechanism for actuating the eccentric bushing 84 are so proportioned that in either limit of motion of the blanket cylinder the line through the axis of the pivots of the link 12 to the crank 14 and the disk I8 passes through the axis of the stud shaft 88, thereby holding the blanket cylinder in either of its set positions.

One arm 54 of the yoke member 48 is provided with spaced lugs I8 and 18 for alternately engaging one arm of a bell-crank 88, the other arm of which engages the plunger 8i of a limit switch mechanism 82 and thus it will be evident that as the yoke member 88 approaches its limit of movement in either direction, it Operates the limit switch mechanism 82. As seen in Fig. 4, the shaft of plunger 8i carries a springpressed lever 83 which abuts a pin 88 carried by a snap switch lever 85. As the plunger 8i is reciprocated, the lever 83 causes snap lever 88 to be shifted moving switch 244 into position to close either the contacts 258 and 258 or the contacts 488 and II. the electrical functions of which will be later described.

Motor I8, which may be of any suitable reversible type. is connected to the pump 28 by any suitable or conventional coupling 88, Figs. 2 and 5, interposed between and secured to the motor shaft 88 and the actuating shaft 98 of the pump 28. The pump 28 comprises a casting 82 formed integrally with the cylinder 38, and a cover plate 84, the pump 28 projecting into and being mounted upon the housing 85 forming the oil reservoir 22. The oil reservoir housing is formed integrally with the support plate 98 for the motor It.

The pump drive shaft 88 is journaled in bushlugs 98 and is provided with'a suitable liquid seal I88 preventing leakage of the liquid along the shaft. A drive gear I82 is cut integrally with the shaft "and meshes with a companion pump gear I84 secured'to a rotatable. sleeve I88 Journaled on a normally stationary but adjustable pin or stud shaft I88 held in position by its shoulder H8 and a cap screw H2. The pump gear I88 is provided with a set of angularly spaced radial passages Ill communicating with similar radial passages H8 in the sleeve I88, the passages II! being adapted to communicate in sequence with slots or chambers H4 and II! formed in the shalt Ill. Liquid trapped between the teeth of the gears at the meshing position is relieved by the passages H4, H6 and the chambers III and II9, the chamber II6 being operative whenit is on the outlet or discharge side 01' the pump as the pump is operating in one direction, and the chamber II9 being operative when it is on the discharge side as the pump is operating in the reverse direction. The chambers relieve the liquid trapped between the teeth of the gears, preventing crushing thereof by allowing it to be relieved back into the exhaust chamber. If desired, the sides of the teeth of the gear I04 may be radially grooved to provide additional relief passages as will be more particularly pointed out hereinafter in reference to the embodiment of the invention shown in Figs. 7, 8 and 9. Also, shaft I08 may be adjusted rotatably to permit the return of liquid from the high to the low pressure side of the pump through the chambers I I6 or H3 in regulatable amounts as determined by the adjustment of the shaft. See, for example, Svenson Patents NOS. 1,912,737 and 1,912,738, dated June The chamber containing the pump gears I02 and I04 is connected to the actuator cylinder 36 by liquid supplying and discharging ports I and I22, the port I20 constituting the inlet and the port I22 the outlet when the pump gears are driven in one direction, and the port I22 constituting the inlet and'the port I20 the outlet when the pump gears are driven in the opposite direction. The port I20 extends into communication with the cylinder 36 above the piston as seen in Fig. 6, and the port I22 extends into communication with the cylinder below the piston.

It will be apparent that in a closed hydraulic system or circuit, such as disclosed, wherein the piston rod occupies a portion of the cylinder on one side only of the piston, there exists a difference in the volume of liquid displaced on opposite sides of the piston per unit of piston movement. In order to compensate for this diiference in volume there are provided two compensating channels or passages I24 and I26 extending through the pump casting 92 radially with respect to the pump gears and from the pumping chamber into communication with the reservoir 22. When the pump gear I02 is driven in a counterclockwise direction as seen in Fig. 6, liquid is supplied to the pump chamber through the port I20 from the chamber I28 above the piston 38 and forced, under pressure, through the port I 22 into the chamber I30 below the piston 38. As the piston 30 moves upwardly or outwardly, less liquid is displaced per unit of movement than is required to fill the space created below the piston by the same unit displacement. Therefore, itmay be stated that less liquid is available for the inlet port I 20 of the pump than must be supplied to the outlet port I22 of the pump to move the piston 34 upwardly. As the piston 38 moves upwardly, a slight vacuum is thereby created in the inlet port I20 due to this difference in the volume of the displaced liquid on opposite sides of the piston and accordingly when each partially filled space between an adjacent pair of teeth of the pump gears I02 and I04 registers with the ports or passages I24 and I26, additional liquid suflicient to illl these spaces is supplied from the reservoir throu h these ports I24 and I26.

When the pump drive gear I02 is rotated in the clockwise direction, as seen in Fig. 6, more liquid is supplied to the inlet port I22 of the pump per unit of movement oi the piston than is required for the chamber I26 above the piston. This surplus liquid creates a slight pressure in the inlet port I22 and is relieved by liquid passage through the ports I24 and I26 into the reservoir 22.

It will be evident from the description of the form of the invention illustrated in Figs. 21 to 6, thatapplicant has provided a very simple and eflicient means for propelling a machine part, a printing press cylinder in the specific embodiment illustrated, and that by reversal of the driv-.

ing motor. the direction or movement of such a machine part may be readily controlled without the use of any additional valve mechanisms.

For installations wherein there is a still greater difference in the volume of liquid displaced on opposite sides of the piston per unit of movement, the invention provides the modification illustrated in Figs. 7 to 9. In this form of the invention the pump gear I04 is provided with two axially spaced sets oi radial passages II4 leading inwardly from the spaces between the gear teeth, and is secured on the rotatable sleeve I06 provided with similar sets of radial passages IIB' communicating with passages II4, the sleeve I06 being rotatably journaled on a second fixed sleeve I36. The teeth of the gear I04 may also be provided on one side with radial slots II5 axially positioned between the sets 01 passages H4.

The sleeve I36 is secured to the pump casting 92 and the cover 94 by a flange I31 formed on one end of the sleeve and a threaded plug I34 secured to the other end thereof. A second threaded plug I39 seals the flanged end of the sleeve. The sleeve I36 is provided with peripheral chambers or slots I40 and I42 gen. erally similar to the chambers H8 and H9, previously described, except that they are axially as well as angularly spaced. The slots I40 and I42 communicate through the sets of radial passages IIB and H4 of the sleeve I06 and the gear I04 with the pump chambers I46 and I44. A shiftable valve member I48 is slidably mounted within the sleeve I36 for movement between the threaded plugs I38 and I39, and this member is provided with a plurality of valve heads I56, I52 and I64. The valve head I52 selectively controls communication between radial ports I56 and I58 and the interior chambers I60 and I64 01' the sleeve I36, the ports I56 and I58 registering with the peripheral chambers or slots I42 and I40 in said sleeve. Chambers I60 and I64 are in constant communication with the main reservoir 22 by means of passages I62 and I66. The valve head I50 seals the chamber I 60 and the valve head I 54 seals the chamber I64. Liquid for shifting the valve member I48 is supplied to the interior of the sleeve I36 on the outer sides of the valve heads I50 and I54 by means of ports or passages I68 and I10 which are connected to the ports or passages I14 and I12 through which liquid passes to and from the chambers I19 and I16 of the cylinder I80, to and from the pump chambers I46 and I44.

As the pump driving gear I02 rotates in a counterclockwise direction, as seen in Fig. 8, liquid is withdrawn from the cylinder chamber I18 on the piston rod side of the piston I32 through the port I14 into the pump chamber I46 and supplied under pressure from the pump chamber I44 to the cylinder chamber I 16 through the port I12, causing piston I82 to move to the right as seen in Fig. 8. The pressure of the liquid in the port I18, which is in communication with the exhaust pump chamber I88. being greater than the pressure of the liquid in the port I68 which is in communication with the inlet pump chamber I86, the valve member I88 is moved to the left to the position shown in Fig. 7. As the piston I82 moves to the right, there is less liquid available per unit of movement of the piston than is required for the cylinder chamber I16. This deficiency of liquid is compensated for by the drawing of the required liquid into the inlet pump chamber I86 from the main reservoir 22. This liquid is drawn from the reservoir through passageway I88, chamber I88, passageway I58 which is now open, slot I88 and passageways H8 and H8 into the inlet pump chamber I86.

When the pump drivin gear I82 is rotated in the opposite direction to effect movement of the piston I82 to the left, as seen in Fig. 8, liquid is withdrawn from the cylinder chamber I18 into the pump chamber I88 through the port I12 and is supplied under pressure to the cylinder chamber I18 from the pump chamber I88 through the port I18. Pump chamber I86 now being on the exhaust or pressure side of the pump, pressure is transmitted through the passageway I68 causing the shifting of valve member I88 to the right, away from the position shown in Fig. '7, opening the passageway I56 and closing the passageway, I58. As the actuator piston I82 now moves to the left, the volume of liquid displaced by the piston from the cylinder chamber I18 is greater than that required for the cylinder chamber I18 per unit of piston mDvement. Passageway I56 now being open, this excess liquid is by-passed from the pump chamber I88 through radial passageways H8 and H8, slot I82, passageway I56, chamber I68, and passageway I62 into the main liquid reservoir.

It will be seen that due to the shiitable valve member I88 the passageways I58 and I58 are closed when on the high pressure side of the pump and open when on the low pressure side thereof to compensate for liquid excess or deficiency. Compensation is made for the diiIerences in volume on the two sides of the actuator piston I82 without any loss of pressure on the pressure side of the pump.

The slots or chambers I88 and I82 not only cooperate with passages I58 and I58 to compensate for liquid excess or deficiency, in the manner stated, but they also act to prevent crushing units I2, I8 and I8 are schematically represented in Fig.,10 as three-phase electric motors 288. 282 and 288 respectively,'although it is to be understood that it is within the contemplation oi this invention to employ any suitable type of motor either of alternating or direct current. Forward and reverse switches 288 and 288 actuated by electromagnets 2I8 and H2 respectively control the forward and reverse connection of the motor 288 to the power supply lines 2, 2I8 and 2". Forward and reverse switches 228 and 222 actuated by magnets 228 and 228 respectively control the forward and reverse connection of the motor 282 to the power supply lines 2, 2I8 and 2I8. Similarly forward and reverse switches 228 and 288 actuated by magnets 282 and 288 respectively control the forward and reverse connection of the motor 288 to the power supply lines 2I8, 2I8 and 218. One push button switch 238 is provided to initiate forward operation of all of the units and one push button switch 288 is provided to initiate the reverse operation oi all of the units. The units I8 and I8 are pro vided with disconnecting switches 288 and 282 respectively to keep these units idle, if desired, when the push button switches 288 and 288 are operated. Thus switch 288 determines whether or not the motor 282 will operate and the switch 282 determines whether or not the motor 288 will operate.

Each hydraulic actuator unit includes a limit switch mechanism 82 as previously described. The limit switch mechanism 01' the actuator unit I2 includes the previously described switch 288 and similarly the actuator units I8 and I8 inciude switches 288 and 288 respectively. The switches 288, 288 and 288 are actuated by the lugs 18 and 18, Fig. 3, of the actuator unit with which the switches are associated, and as will be seen from Figs. 2 and 3, these limit switches, whentrlpped by one of the lugs, remain in tripped position until engaged by the companion lug oi the pair .when the actuator has been moved to its other limiting position.

For the purposes of description, it will be assumed that all of the actuating units are at the limit of their reverse movement and that the limit switches 288, 288 and 288 have accordingly been moved to the positions shown in Fig. 10 to partially complete the circuit to th actuating magnets H8, 228 and 282 of the forward control switches 288, 228 and 228. Accordingly upon actuation of the push button 288, assuming the of the fluid in the manner previously described the chambers to prevent crushing of the liquid at the base of the teeth of the gear I88, and the radial slots H5 in eflect communicate with passages II8 and H8 to prevent crushing of the fluid at the base of the teeth in the gear I82. The chambers I 88 and I82 remain operative to prevent fluid crushing even when the associated passageways I58 and I58 are closed.

Any desired number of the described hydraulic actuating units may be controlled selectively from one pair of push button switches. For the purpose of illustration there is shown in Fig. 1 an installation comprising three such units I2, l8 and I8. Fig. 10 illustrates the schematic electrical circuit for selectively controlling the three units of such installation from a single pair of push button switches. The motors I8 of these main switch 2I8 to have been closed connecting the supply lines 2, M6 and M8 to the main power lines 2I8a, HM and 2I8a', a circuit will be completed to the actuating magnet 2I8 from the supply line 2 through the contacts 258 and 282 of the push button switch and wire 258, the limit switch contacts 256 and 258, the wire 288 to the actuating magnet 2I8; and from this magnet through the wire 282, the wire 268, the wire 288, the contacts of overload relays 238, 218, 212, 218, 218 and 218, and wire 288 to the supply line 2I8. Similarly the closing of push button 238 completes a circuit for the actuating magnet 228 from the push button to the wire 282, to the wire 288, the wire 288, the contacts 288 and 298 of the limit switch 288, and the wire 282 to the actuating magnet 228; and from the magnet 228 to the wire 288, the wire 288, the contacts of the disconnecting switch 288, the wire 288, the wire 888 and the wire 288, the overload relay switches 288 to 218 inclusive and the wire 288 to the supply line 2 l8. The actuating magnet 282 is connected :00, 2c: and 204 and the completion or holding circuits as will now be described. I

The motor lead 3" is connected by the switch arm 3| 6 and the wires'3l8 and 320 to the supply line 2| 8. Similarly the motor leads 322 and 324 are connected by the switch arms 326 and 326, and the wires 330 and 332 and the wires 334 and 336 to the supply lines 2|6 and 2 respectively. The contact arm 338 or the forward control switch 206 competes a holding circuit for the actuating magnet 2i0 from the supply line 2" through the wire 336, the wire 334, wire 340, contact am 338 and the wire 282 to the wire 234 around the push button switch contacts 230 and 252.

Similarly the leads .342, 344' and 346 for the motor 202 are connected bv the arms 348, 350 and 352 of the forward control switch 220 to the power supply lines 2 i8, 2 I 6 and 2 l4 rer pective y through 240, wire 238, wire 300, wire 266, overload switches 268 to 278 and the wire 280 to the line wire 2i3, The leads 312, M4 and 376 for the motor 204 are similarly connected by the arms 318, 380 and 382 of the forward control switch 228 to the supply lines M8, M6 and 2 re pectively through the wires 384, 386, 338 and the wires 398, 392 and 384. The contact arm 396 of the forward control switch 228 comp etes the holding circuit for the actuating magnet232 from the supply line 2l4 through the wire 394, the wire 388, the wire 398, the arm 33%, the wire 400, the wire 284, wire 302, contact 304, switch 248, contact 306, wire 308, magnet 232, wire 3H3, wire 3l2, switch 242, wire M3, wire 380, wire 266, overload switches 268 to 238 and wire 280 to the line wire 2i8. Any other desirable means may be employed in place of the contact arms 338, 366 and 386 for completing other conventional circuits for locking the actuating magnets 2i0, 224 and 232 in their switch closing position.

From this de cription of the forward control circuits it will be evident that the disconnecting switches 240 and 242 being in their on posimoving the switch 244, Fig. 10, to the right. This movement of the switch 244 breaks the circuit between contacts 264 and 238, thereby breaking the holding circuit for the actuating magnet 2|. which in turn allows the forward control switch to move to open position, breaking the circuit to the motor. Similarly the limit switches 246 and 248 when actuated break the holding circuits to the actuating magnets 224 and 232, and these magnets in turn deenergize thecircults for the motors 202 and 204i It is to be noted that the holding circuits for the actuating magnetslll,

224 and 232 are all arranged in parallel so that the breaking of any holding circuitdeenergizes only its own associated actuating magnet.

The limit switches 244, 246 and 248- being in their reverse motor position, depression of the reversing push button 238 will complete circuits through these limit switches through the actuating magnets M2, 226 and 234 which operate the reverse control switches 208, 222 and 230. The depresson of the push button switch 233 connects supply line 2 l4 to actuating magnet 2l2 through .the swtch contacts 402 and 404, wire 406, contacts 408 and 0 of the limit switch 244 and wire 2 to the actuating magnet 2II2. 0n

the other side of the actuating magnet t2i2 the c rcuit is completed through the wire M4, the

' wire 262. wire 264, wire 266, overload relay contacts 268 to 218, and wire 280 to supply line 2i8.

The crcuit for the actuating magnet-226 is completed irom the contact 404 of the switch 238 through the wire 6, wire 8, contacts 420 and 4220f the limit switch 246, wire 424, the actuating magnet 226, wire 426, the w re 286, the contacts through the cont ct 404 of the switch 238 to the wire M6. wire .428, the contacts 430, 432 of the limit switch 248, wire 434, the actuating magnet 300, the wire 266,- overload relay switches 268 to 218, and wire 280 to supply line 2i8.

tion, the momentary closing of the push button switch 236 results in the energization of all of the motors for cperation'in the forward direction. These motors 200, 202 and 204 drive their respective hydraulic pumps which in turn drive their hydraulically associated pistons in the forward direction. As each piston reaches its limit of movement in the forward direction, the limit switch associated therewith will be moved to its opposite position. For example, at the end of the upper stroke of the piston 38 or I82 of the unit i2 the lug l8 willengage and operate the bell-crank 80 which in turn will move the plunger 03 to the right as seen in Figs. 2 and 3, thereby Thus the closing of switch 238 causes the reversing magnets 2| 2, 226 and 234 to be energized 442 of the reverse control switch 208 connect the motor leads 3, 322 and 324 to the supply lines 2i4, U6 and 2i 8 respectively through the wires 336, 332 and 320. It will be seen that the motor leads 3| 4 and 324, which upon operation of the forward control switch 206 were connected to the supply lines 218 and 214 respectively, are

now connected by the reverse control switch 203 43 in opposite phase relation, the lead 3 i 4 being connected to the supply lines 214 and the lead 324 being connected to the supply line 2| 8. Hence, upon operation of the control switch 208, the

motor will be energized for reverse rotation. The.

'11 of the push button switch 233, the circuit to the magnet being establishedthrough wire 400 and contacts 408 and 0, as previously described in reference to the actuation of the push button switch.

In like manner the switch arms 443, 450 and 452 of the reverse control switch 222 connect the motor leads 342, 344 and 343 to the supply lines 2, H6 and 210 respectively through the wires 334, 302 and 300 so as to energize the motor for reverse rotation. The arm 454 of the reverse control switch 222 completes the holding circuit for the actuating magnet 223 around the push button switch 238, this holding circuit being completed from the supply line 2 through the wire 334, the wire 358, the wire 368, switch arm 454, wire 453, and wire 413, the circuit then continuing through wire H8, and contacts 420 and 422 to the magnet, as previously described in reference to the operation of the push button switch 233.

In similar manner the switch arms 458, 466 and 482 of the reverse control switch 230 con-' nect the'motor leads 312, 314 and 316 to the supply lines M4, 216 and H8 respectively through the wires 394, 392 and 390 so as to energize the motor 204 for reverse rotation. The arm 464 of the reverse control switch 230 completes the holding circuit from actuating magnet 234 around the push button switch 238, this circuit being completed from the supply line 2i 4 to the wire 334, the wire 388, wire 398, switch arm 464 and wire 4! 3, and then through wire 420 and contacts 430 and. 432 to the magnet as previously described.

Aseach actuated part or piston of the several hydraulic actuating units reaches its original position or lowermost position as seen in Figs. 1 to 3, the lug 16 of each actuating unit engages and actuates the bell-crank 80, Fig. 3, thereby moving the limit switches to their original position, as shown in Fig. 10, whereby the holding circuit for the actuating magnet of the reverse control switch is broken and the circuit to the actuating magnet of the forward control switch partially completed. Each limit switch controls only its own holding circuit, thereby insuring that the deenergization of each motor unit will be under the control of its own limit switch.

In a multiple unit system it is sometimes necessary to maintain the second and third units idle while the first unit operates, or to maintain either the second or third unit idle while the other two units operate. In such a case it is only necessary to manually operate the disconnecting switch 240 or the disconnecting switch 242 to an "ofl" position. The switch 240, when in oil position, breaks the circuit to both of the actuating magnets 224 and 226 disconnecting the common wire 298 from the common wire 296. The switch 242, when in "oiP position, disconnects both actuating magnets 232 and 234 by breaking the circuit between their common wires 3l3 and 312. Hence, when the switch 240 or the switch 242 is in off position, the motor 202 or the motor 204 will not be operated by the closing of either the push button 235 or the push button switch 238.

In Figs. 11 to 27 there is disclosed a hydraulic actuator system for the control of an installation of valves or the like as in a piping system, which may, for example, be a gasoline or oil refining process, such as the Houdry oil refining or cracking process described in Fortune Magazine, February, 1939, pages 56 to 58. In systems or this type the various valves in the installation must be opened and closed quickly and eiiioiently in a predetermined timed sequence, and each valve must be closed with a predetermined accurately controlled actuating pressure. Remote control, and remote and accurate indication of the valve position may also be essentials. To overcome sticking caused by various operating conditions, additional actuating force must be applied for initially moving or breaking the valve away from its seat to open the valve. Also, while the valve must be firmly retained in closed position when such is-required, allowances must be made for the wide temperature variations to which the valve may be subjected, precluding damage resulting from temperature induced expension of the valve parts. These and other requirements are met by the actuator system provided by the present invention.

More specifically, in piping systems such as above mentioned, the valves are subjected to extreme variations in temperature, but notwithstanding these temperature variations, the valves must positively cut oil communication within the conduit system under all conditions of service when in closed position, and at the same time must be actuated positively from fully closed to fully opened position in a minimum oi. time and without damage to the valve structure. It the valve is positively or mechanically locked in closed or seated position, when the valve is subjected to increased temperature, the expansion of the parts tends to freeze the valve member to its seat or in its guides requiring very high operating forces to break the valve from its seat when the valve is again to be opened, and in some instances actually causing rupture or breakage of the structural parts. In accordance with the invention the valve may be closed with a predeterm ned controlled pressure, and if desired also locked in closed position. But the locking means is yieldable to permit the necessary expansion of the parts due to temperature changes precluding freezing of the valve seat or rupture of the metal structures.

Although the invention provides means for applying a high initial opening force to the valve member to break the same away from its seat, the forces applied to move the valve member throughout the remainder of its range 01' travel are of less magnitude reducing wear and pounding of the valve parts and the actuating mechanism. Further, the final closing force applied to the valve member to urge it into closing engagement with its seat may be accurately controlled whereby to apply the proper or desired locking eifort to the valve closing operation.

As illustrated in Fig. 11 a multiple valve installation is shown wherein hydraulic actuator mechanisms of the general type previously described, but embodying certain variations and modifications, are provided for moving the valve elements to open and closed positions under the extreme operating conditions discussed; and ineluding simplified controls and interlocking means by which any number of the hydraulic actuating'means may be operated in sequence and in timed relation, such interlocking means preventing false operation of any unit ii a unit which should have been previously operated has 10 failed to operate at the proper time. Referring more specifically. to Fig. 11, the piping system shown may comprise a main pipe line 500 and auxiliary pipe lines 502, 504 and 500 through which various treating agents may be introduced into the main pipe line or through which liquid or canon 13 fluid therein may be withdrawn. Valves 598, l9, H2 and 514 are provided in the pipe line to control the flow of fluid therethrough and to the various auxiliary pipes. These valves are provided with hydraulic actuating units 5| 6, ill, 52!] and 522 respectively.

These hydraulic actuating units may be interconnected for operation in predetermined timed relation as shown schematically in Fig. 25 subsequently to be described. Remote indication of the position of each valve may also be provided. as will hereinafter be set forth in reference to Fig. 25, and also Figs 26 and 27.

.Each of the valve structures and their associated hydrau ic actuating units 5l6 through 522 is identical in construction, and therefore the description of one will suffice for all. As shown in Fig. 20, each valve comprises the usual valve housing 524 having removable valve seats 525 adapted to be engaged by the shiftable valve member or head 528 carrying the non-ferrous metal seating rings 529. The valve head 528 is secured to and operated by the valve rod 539. The valve rod 538 extends upwardly from the valve head through the bonnet 532 secured to the valve housing 524 by the screws 538, the bonnet bein provided with the usual packing means 540 between the bonnet and the valve housing. The bonnet 532 is extended upwardly (Fig. 11) to provide a yoke 542 which forms the support for the hydraulic actuating unit. The bonnet 532 is provided with a packing nut 544 for retaining the packing means 546 in position in the upper sleevelike portion of the bonnet about the valve stem 558 to prevent leakage of the fluid along the valve stem.

As best seen in Fig. 12, the valve stem 539 is connected to the actuating piston rod 548 of the actuating unit by coupling rings or collars E59 and 552 between which is inerposed a disk 554 of any suitable heat insulating material for preventing transference of heat to the actuator from the valve stem 558. The upper coupling ring 552 is provided with an integral arm 553 extending outwardly from between the arms of the yoke 542 which is adjustably connected at its outer end to the actuating rod 555 of a limit switch interlock mechanism 558. The switch mechanism 559 and the hydraulic actuator 560 are individual- 1y mounted on a base plate 562 bolted to the yoke 542. By this method of connecting the hydraulic actuator and the switch mechanism of each actuating unit to the valve structure, it is possible to remove either the hydraulic actuator 568 or the switch mechanism 558 without disturbing the other which is of great importance in certain installations where a number of valves are interlocked together as in the Hcudry cracking system previously noted. An adjustable packing nut 563 is threadedly secured to an extension on the actuator end cap 564, for retaining the piston rod packing 565 in place.

Referring more specifically to th actuator unit, main cyinder casting 566 contains two different size cylinder bores 5'68 and 515, of which the upper bore contains the piston 512 secured to the upper end of the piston rod 546 and the lower bore contains the floating piston 514. is provided with a reduced head portion 516 extending upwardly into the smaller bore 568. Piston 514 and head 561 move as a unit and are provided with suitable seaing rings which form a seal for the fluid pressure during movement of the piston as will later be apparent. Each actuator unit includes a prime mover such as an elec The piston 514 tric motor 518 (Fig. 13), a pump 580 and fluid reservoir 582, mounted on a support 584 which is preferably cast integrally with the main cylinder casting 566, although it may of course be cast separately and secured in a conventional manner to said cylinder casting. A pressure controlling switch mechanism 586, the function of which will be later described, may also be mounted on the support 584.

The pump 58!] may be similar in construction to the pump shown in Figs. 5 and 6 or in Figs '7 to 9, the main casting of the pump forming with the support 584 one wall of the oil reservoir 582, the other walls of which ar formed by the housing 568. Thepump may be mechanically connected to the motor 518 in the manner shown in Fig. 13, the coupling 59!] being enclosed within the support 584. The ports or passages 592 and 594 connect the inlet and outlet ports 596 and 596 of the pump to the upper end of the cylinder bore 568 and to the lower end of the cylinder bore 519,

the ports or passages 592 and 594 being formed in the pump casting, the support 534, and the main cylinder casting 566, eliminating, the need for any outside piping between the pump and the cvlinder. A filld passage or port 609 extends through the main cylinder casting 566 from the upper end of the cylinder bore 568 to the lower cylinder 519. The enarged central bore 602 of th piston head 516 provides a fluid passage about the piston rod 548 permitting the fluid to pass from the under side of the piston 514 to the under side of the piston 512.

Assuming the valve to be closed as shown in Fig. 12, upon rotation of the motor in a direction to effect an upward movement of the valve stem 539, the pump 580 will draw fluid which is preferably oil from the cylinder bore 568 above the piston head 512 through the port 592 into the pump port 596 and force fluid through the port 598 and the port 594 into the cylinder bore 519 below the piston 514. Differences in the cylinder volumes on opposite sides of the pistons are compensated for as previously described. The power or floating piston 514 under the force of the fluid moves freely for a predetermined distance determined by the space 504 until the upper end of the head portion 516 strikes the lower wall of the piston 512. It will be evident that this free movement of the piston 514 permits the motor to attain full speed before the piston 514 engages the piston 512, through which piston and the piston rod 548 the upward force of the large piston 514 is initially applied to the valve stem to lift or break the gate valve head 528 from its seats 526.

The piston 514 itself moves only a predetermined selected distance suificient to free the gate valve from its seats and is then stopped by the upper wall of the cylinder bore 510'. The sealing rings for the head portion 516 of the piston 514 prevent the fluid, which now passes through the central bore 602 to the cylinder bore 568 beneath the piston 512, from entering the port or passage 600. The valve gate being now free from its seat and partly open, the only force required to lift the valve is substantially that necessary to overcome the frictional resistance of the valve packings and the weight of the parts involved, and therefore the small piston 512 can now be used to complete the opening of the valve. The piston 512 is moved to complete this opening of the valve by fluid supplied through the port 594 and the central bore 602 of piston head 516 to the under side of the piston 512. Since the area of the under. face of the piston 512 is considerably smaller than the under face of the pis ton 514, and since a smaller volume of fluid will therefore move the piston a greater distance, the piston 512 will move at a suitably faster rate of speed after the piston 514 has completed its movement to free the valve.

As the piston 512 approaches its normal limit of movement in the upward direction, the switch rod 556 will cause the operation of the interlock and switch mechanism 558 to break the circuit to the motor 518 in a manner to be later described. After opening of the valve, the frictional resistance to movement of the parts, and the resistance to circulation of fluid through the several passages or ports may be relied upon to prevent the weight of the valve from moving it toward a closed position.

Upon energization of the motor 518 to eifect a closing of the valve, fluid will be withdrawn from the cylinder chamber 568 beneath the piston 512 and from the cylinder chamber 510 beneath the piston 514 through the port 594 to the pump port 598, and forced under pressure through the pump port 596 and the port 592 into the cylinder chamber 568 above the piston 512. Fluid is also forced into the cylinder chamber 516 above the piston 514 from the cylinder chamber 568 through the port 608. This movement of the fluid forces both the pistons 512 and 514 downwardly to effect a closing of the valve.

When the valve gate reaches the seating position, the pressure on the top of the piston 512 builds up to a predetermined value as determined or controlled by the switch mechanism 588, and

when the switch mechanism operates the motor 518 is deenergized. This seating pressure may be varied over a wide range to suit different operating conditions and different sized gate valves so as to close the valve gate leak-tight but without jamming or scoring of the'valve seat.

More specifically, referring to Figs. 14 to 16, the pressure switch mechanism 586 comprises a main body casting 666 in which is mounted a pressure relief valve structure or device 608 and a normally open pressure switch structure or mechanism SIG. The main body casting 606 may be secured to the top of the support 584 in any suitable manner as for example by the screws 612. A port 6|4 connects the inner end of the relief valve structure 608 to the port 592 of the hydraulic actuator by the fluid coupling 616 and the port 618, the coupling 616 being of suitable leak-proof character and preferably being of a structure described in applicants Patent No. 2,395,518, dated February 26, 1946. As the valve gate closes, the piston 512 is frictionally retarded and this causes a building up of fluid pressure on the upper side of the piston 512. This increased fluid pressure is transmitted to ports 592, 618 and H4 and acts on the head of a valve stem 620. At a predetermined pressure, as determined by the tension of a compression spring 622, the shiftable valve 624 will be moved from its seat and simultaneously the annular sealing ring 626 formed on the valve stem will be moved from its cylindrical sealing surface into the larger bore 621.

The tension of the spring 622 which determines the pressure at which the valve 624 will operate may be adjusted to a desired value by means of the adjusting screw 628 against which the spring abuts at its lower end, the screw being rendered accessible upon the removal of end closing cap 629.

Upon opening of the valve 624, fluld passes from the port 614 through an axial port 636 and a radial port 632 in the valve stem 626 and past the open annular seal 626 into a port 634.

From the port 634 the fluid passes by means of the port 638 into the chamber 638 at the inner end of the stem 646 of the switch mechanism 610. The pressure of the fluid in the chamber 638 acting on the head 642 of the stem 640 moves the stem outwardly against the force of the compression spring 644, and this movement of the stem causes the contact ring 646 to engage and connect the fixed contacts 648 and 658. The contacts 648 and 650 when connected together cause a breaking of the motor circuit and stop the rotation of the pump.

The port 634 is connected back to the main oil reservoir 562 by a port 652 (Fig. 16, indicated.

also by dot and dash lines in Fig. 14) having a plug 654 providing a restricted orifice 656, an 'annular port-or chamber 658, and a port 660 extending from the annular port 658 through the main body 606 of the pressure switch mechanism 566 and through the support 584 into the interior of the oil reservoir 582. The restricted oriflce 656 serves three purposes, namely: first, to allow 'a' sufficient pressure to be built up in the chamber 638 to operate the switch mechanism 610; secondly, to relieve the pressure in this chamber after the valve 624 has been closed so as to permit the stem 640 of the switch to be returned to its initial position by compression spring 644; and finally, as a fluid overload or by-pass in case of failure of the electric control circuit resulting in the continued operation of the pump after the valve 528 has been seated in which latter case 'all the fluid delivered by the pump is returned to the oil reservoir through the orifice 656 at a pressure higher than that required to operate the switch mechanism 6 l 0. f

The contacts of the switch mechanism 6" may be enclosed in a detachable explosion-proof housing 662, which may also be formed to provide a housing for the closing cap 629 which encloses the adjusting screw 628 of the pressure relief valve structure 608.

The adjustment of screw 628 determines the force with which valve 528 will be thrust into engagement with its seat.

In addition to the foregoing automatic electric motor operation, each hydraulic actuating unit may be manually operated by means of a hand wheel 564, Fig. 11, mounted on the extending end of the shaft of the motor 518 and operatively connected thereto by any suitable dis- I engageable clutch not shown, by which the hand a guide for a collar 612 secured to the upper 4 end of the rod 556. The upper end of the rod 556 is threaded as shown to adjustably receive spaced collars 614 and 616 which form the means for actuating the interlock switch device 156, the collars 614 and 616 being retained in adjusted position by lock screws 688 and 682 respective- The switch device comprises a plurality of sets or pairs of leaf springs carrying the sets 15 of electrical contacts 152, 154, 156, 158 and 154 aaoaaoe and mounted upon a common block or blocks of insulation 684 attached to brackets 686 carried by a mounting plate 680, and mounting plate 688 also carrying an electrical panel board 680 which may be provided with the usual terminals perinanently wired to the contacts of the switch device and by'which the external connections to the switch may be varied as desired. The switch I50 comprises upper and lower parts 692 and 684 which are selectively operable by the roller 686 mounted on a crank arm 633 secured to a stud I carried by the mounting plate 688. The stud I00 also has fixed thereto a crank arm I02 provided at its outer end with a. roller I04 lying in the path of movement of the actuating collars 614 and 616, and actuated thereby as the rod 566 approaches its upper and lower limits of movement. A counterweight I06 secured to the stud I00 or to the crank arms 688 or I02 as desired, balances the arms allowing the parts to assume the position shown in Fig. 17 when the roller I04 is not engaged by either of the collars 614 and 616. Figs. 18 and 19 illustrate the different positions to which the crank 688 and roller 696 and associated switch parts are moved by the collars 614 and 616 on operation of the actuator. It will be seen that when the roller I04 is not engaged by either of the actuating collars, the'two sets of contacts I60 and I58 oi the upper switch part 692 and the lower contacts I54 and I52 are open, while the other upper switch contacts I56 are in circuit closing position. As the gate valve approaches its closed position, the actuating collar 616 will engage the roller I04 and move the roller 696 downwardly, thereby moving the contacts I54 and I52 into circuit closing position (Fig. 19). As the gate valve reaches its normal limit of movement in the upward direction, the actuating collar 6 will engage the roller I04 and move the roller 696 upwardly to effect a closing of the two sew of contacts I60 and I58 of the switch part 692, but to break the circuit between the set or contacts I56 of this switch part, as seen in Fig. 18.

Fig. 25 discloses schematically the electrical control circuits for operating a system providing three of the hydraulic valve actuating units previously described, automatically in a predetermined sequence, or manually at will. For purposes of illustration the system is shown as comprising three-phase motors I08, H0 and H2, although it will be evident that any other alternating current motor may be used as well as any direct current motor, each of these motors being used as the motor 518 for driving the pump 580 of a hydraulic actuating unit. It is also obvious that the system may comprise any desired number or actuating units as the occasion may require.

In the manual operation of the system, the push button switches H4, H6 and I I8 individually control the actuating magnets I20, I22 and I24 for the forward control switches I26, I28 and I30, while the push button switches I32, I34.and I36 individually control the actuating magnets I38, I40 and I42 of the reverse control switches I44, I46 and 148. For purposes of description, it will be assumed that initially the first actuator is standing in the valve closed position. In this case its interlock switch I50 will be in the position shown in Fig. 19 in which the pairs of contacts I52 and 154 of the lower set are in circuit closed positions as is also the contact pair I56 of the upper set, while the pairs of contacts I58 and I60 of the upper set are in circuit open posi- 18 tion. The green indicating lamp I62 is thus energized through acircuit from the supply line L-l through a wire I64, the lamp I62, the wire I65, contacts I56 and the wires I66 and I68 to the supply line L-3. This lamp 162 indicates that its valve is in closed position.

Upon depression of the valve opening switch N4, the circuit to the actuating magnet I is completed irom the supply line L3 through the wire 168, the wire I10, the push button lie, the wire "2, the actuating magnet I20 and the wire I64 to the supply line L-I. This magnet therefore actuates the forward control switch 220, the arms of which connect the motor leads I I4, lie and 118 to the supply lines L-l, L-2 and L-I respectively through the wires I84, I82 and I80, and wires 186, I88 and I68.

The arm I90 of the switch I28 completes a holding circuit for the actuating magnet I210, this circuit being completed from the supply line L-l through the wire 164, the actuatin magnet I20,

the wire I92, the arm I80, the wire 194, the interlock contact I56, wire I66 and wire I68 to the.

supply line H.

Simultaneously with the energization of the actuating magnet I20, the switch actuating magnet I96, which is connected in parallel with the magnet I20 is also energized and this magnet operates a switch I98 to complete a circuit for the red lamp 000 from the supply line L-I through the wire I84, the lamp 800, the wire 802, the switch 198, the wire 804 and the wire I68, to a supply line L-3. The green lamp I62 and the red lamp 800 are now both lighted, thus indicating that the valve is between open and closed positions; thus, if for any reason the valve should for failure of any cause remain between the opened and closed positions, the illumination of both lamps will indicate such fact. Also these lamps; may be used at a remote panel board for indicating the fact that the valve is moving.

As the valve actuator completes its normal opening stroke, the rod 556 operates the interlock switch I50; thus in the case of the first unit breaking the holding circuit for the actuating magnet I20 at the interlock contacts I56. The magnet I20 being thus deenergized, the forward control switch I26 is returned to open circuit position, breaking the motor circuit and the motor 108 stops rotating. The opening of the interlock contacts I56 also breaks the circuit to the green lamp I62 which is thus extinguished, but the circuit to the red lamp 800 remains energized through the switch I98 for the switch I08 is moved to its opposite positions only upon energization of the magnet I86 or the magnet 806. The red lamp 000 therefore now indicates that the valve is standing in opened position.

Upon operation of the valve closing push button switch I32 a circuit will be completed for the actuating magnet I38 of the reverse control switch I44, this circuit being completed from the supply line L3 through the wire 808, the push button I32, the wire 906, the wire M0, the actuating magnet I38 and the wire 8 I 2 to the supply line L-I Upon operation, the reverse control switch I44 connects the motor leads I14, I16 and I18 to the supply lines L-3, L--2 and L-l respectively through the wires I68, I88 and I86. This completes the motor circuit and the motor begins to rotate in a valve closing direction. The holding circuit for the actuating magnet I38 is completed by the switch arm 8 from the supply line L-I through the wire M2, the actuating magnet I38, the wire 8I6, the switch arm 8,

As the valve actuator starts to move in a closing I direction, it allows the interlock switch to return to its neutral position, closing contacts I and the operator that the valve actuator is in motion.

As the valve actuator completes its closing stroke, hydraulic pressure is built up in the cylinder of .the pressure switch device 6 III, Fig. 14, and schematically represented in Fig. 25, thereby completing a circuit from the supply line L--I through the wire I, the magnet 808, the contacts of the pressure switch Bill, the wire 822 and the wire I68 to the supply line L-4. The magnet 808 then moves the switch I98 to open circuit position, thereby breaking the holding circuit for the actuating magnet I38 stopping the motor and also breaking the circuit for the red lamp IN. The green lamp I82 remains energized, however, thus indicating that the valve has been brought to closed position. The valve actuator as it completes its closing stroke also actuates the lower part 694 of the interlock switch I50, as shown in Fig. 19, to close the contacts I54 and 152 for a purpose which will presently appear in connection with automatic operation.

The manually controlled circuits for the motors III and H2 for the second and third actuating units are identical to the manually controlled circuits for the motor I08 and need no further description other than to state that push button Iii initiates the operation of the second actuator unit in the valve opening direction, that push button switch H8 initiates operation of the third operating unit in a valve opening direction, while push buttons I34 and 136 initiate operation of the respective actuating units in a valve closing direction. The interlock switches 82! and 826 for the second and third actuator units are operated by their respective units in the same manner as interlock switch I50 of the first unit. Position indications are given for the second unit by lamps 828 and 830, correspondng to the lamps I82 and 800 of the first actuator unit, and similarly, lamps 832 and 834 provide position indica-. tions for the third unit. Pressure operated switches 836 and 838 for the second and third.

actuating units, correspondng to the pressure operated switch 610 for the first unit, control the limit of movement of the second and third actuating units in the valve closing direction.

In many installations of valve actuators it is .necessary that the valves which are controlled shall be operated in some predetermined sequence, and that this sequential operation shall be accomplished automatically when once initiated or in continuous repetitious cycles of operation. It is also often necessary for the successful operation of such a system that a valve be not operated unless others of the valves are inthe three units shown are to be operated continuously in numerical sequence and at equal intervals. For example, assuming all valves to be closed, it is assumed that it is desired to first open the valve of the first unit, then alter a predetermined interval open the second valve. and after the lapse oi a like interval, open the third valve; and that it is further then desired after the lapse of the same interval to close the first valve, and successively at equal intervals. then close the second and third valves. The cycle 01' operation will then continue in the same order with all time intervals equal.

The illustrated interlocking system provides means for preventing any valve from being moved unless the other valves stand in the position that they should occupy at the time that the first mentioned valve should be moved. For example, the valveof the first unit may not be opened unless the valves of the second and third units are closed, nor may the valve of the first unit be closed unless the valves of the second and third the valve of the third unit be closed unless the valves "of the first and second units are both closed.

The time intervals between the movements of the valve actuators are provided by a multicontact switch mechanism comprising a plurality of interconnected switches, of which the contacts are shown in Fig. 25 as 840, M2, 8, Ni,

40 848 and 850, there being in the assumed illustration two sets of such contacts for each or the actuator units. These contacts are actuated by a series of synchronously operated cams 852 to 862 which may, if desired, be mounted on and driven by a singleshait, which shaft may be continuously'rotated by some suitable clock mechanism or synchronous electric motor, such as the three-phase synchronous motor I. is provided with a contact actuating projection on its periphery and these cam projections are angularly related to each other in such a way that they will operate the contacts in the desired order and after the desired predetermined intervals. In the illustrative example, a complete cycle of operation of the valves is efiected in one revolution of the common cam shaft, and since all intervals between the actuation of the units areto be equal, the projections on each of the cams 852, I58 and lit which control the opening movement of the valve actuating units are displaced by the same angle of 60 degrees from the preceding cam, while each of the cams 854, 858 and 882 which control the closing movements ofthe actuating'units is similarly displaced fror'n the preceding cam by an angle of 60 degrees.

It should further be noted that since in the assumed example, the cycle is to be repeated after a lapse of an interval equal to the interval between the actuation oi. each valve in the cycle, the projection on the opening control cam II! is displaced from the projection on the closing cam 862 by an angle of 60 degrees.

In the assumed example at the beginning oi the cycle or operation, all valves are in closed Eachcam. 

